Manual telephone system



Jan. 11, 1927.

J. H. LEVIS. JR

MANUAL TELEPHONE SYSTEM 2 Sheets-Sheet 1 Filed Sept. 28, 1923 MOELO m mOEuO v art INVENTOR JOHN H.LEVlSvJR. BY AW.

ATTORNEY Jan. 11 1927. 1,614,440

J. H. LEVIS. JR

MANUAL TELEPHONE SYSTEM Filed Sept. 28, 1923 2 Sheets-Sheet 2 Wv-{h- 13- Kj f a all kg Hil I! t E |==0- D I 3 E W 11" e a I 2 I II E "K H m w v E :5 g I M n c. .-'=D- N\ 9 a w J O i- E l I *1 $5 5 fi,

N a: A m 25 33 50 I6 6 INVENTOR JOHN wuzvlsqR.

BY A).

ATTORNEY Patented Jan. 11, 1927.

our-rs. stares JOHN H. LEVIS, 53., 013 RQCHESTEB, NEW YOR ASt-SEGNOR TO THE $TROIiiBEBG-CARL- SON TELEPHONE MANUFAGTUTLTEC'G CGMPANY, OFROCHESTEB, NEW YORK, 1A GOR- IOBATION O NEVJ YORK.

MANUAL TELEPHONE SYSTEBE.

Application filed September 28, 1923. Serial No. 665,479.

This invention relates to telephone sys tems and is especially adapted for manual telephone systems.

In former telephone systems, much ditliculty was encountered in maintaining the proper operation of the supervisory means at one otlice for controlling the supervisory signals at a second o'liice of a multi-oilice sys- 'tem. In accordance with one arrangement for plOVlfllIlQ, supervision in a multi-oliice telephone system, a supervisory relay at the called ollice provided with a high and a low resistance winding was included in series with a supervisory circuit including the two sides of a trunk circuit extending to the originating ofiice, where a marginal supervisory relay was serially included in the con nection. The marginal relay was so designed that it did not operate in series with the high. resistance winding of the supervisory relay at the distant oliice. When the called party answered the high resistance windings ot the supervisory relay was removed from the mentioned series and the marginalrelay at the originating oiiice was operated to control the supervisory signals. If, however, the series circuit was temporarily interrupted due to the A operator breaking the connection and then reestal lishing the connection While the called party was maintaining his portion of the connection the high resistance winding of the supervisory relay was shunted so that it then became necessary for the mentioned supervisory relay to operate through its low resistance winding. This necessitated that the supervisory relay be designed with great care and further necessitated very careful maintenance of the same.

One of the main teatures'of this invention is as arrangement whereby the supervisory means including the supervisory relay at the called o'llice will operate with greater accuracy and with much less maintenance than in former systems.

Another feature of the present system resides in the provision of means whereby in a manual telephone system having a single set ot'eommon r31 ing lreys for each operators position ringing current is withheld trom the called line whenever connection is made to this line at a time when the receiver at its substation otl the switch hook,

The drawings with Figs. 1 and 2, arranged in the order named, diagrammatically represent a telephone system, incorporating the present invention. At the left of Fig. 1 there is represented a subscribers sub-station and line equipment which terminates at an A. operators position located at one manual exchange. Near the center of thisifigu-re there is represented a single manual cord circuit located at one of said A operators positions. At the right of the dotted line in Fig. 1 and in Fig. 2 there is shown a trunk circuit leading from the A otfice to a 'B operators position at a second oflice. At the extreme right of Fig. 2 there is shown a subscribers sub-station and telephone line terminating at the B o'l'lice.

It is believed that the "invention will best be understood by describing the method of establishing a telephone connection from a subscribers line such as that indicated at C, which terminates in one manual o'tfice, to a subscribers line designated D, which terminates at a second otficc. When the subscriber at C initiates a call by removing his receiver from its switchheok, the .line relay 5 is operated in the well fknownmanner over the two sides of the subscribers line in series, and when operated, it lights the line lamp 6 associated with an answering jack of the telephone line located atian A operators position at the A oiiice. The A operator on noting that the line lamp 6 is lighted, inserts the plug P of one of her cord circuits into the jack J of the calling line. This is etlective to extend theea'lling line through the tip and ring'conductors of the cord circuit through both windingsin series of the supervisory relay 11 to ground and grounded battery respectively.

At this time the sleeve relay 8 is also actuated in series with the cut-off relav 9 and as is well known, the cut ofi relay disconnects the line relay from the calling line and extinnuishes the line lamp 6.

The sleeve relay 8 closes a break point in the circuit of the answering supervisory lamp 10, but at this time the circuit of this lamp is open at the armature and back contact of the answering supervisory relay 11. The A? operators telephone set is then connected to the calling telephone line either by a listening key (not shown) or by 'meansof relay means (not shown). The A. operator thereupon inquires the number of the wanted telephone line and as soon as she discovers that the wanted line terminates at a distant oflice, she communicates with a B operator at the oiiice over an order wire (not shown) and the B operator assigns a trunk circuit for use.

Let it be assumed that the trunk circuit assigned is that shown in F 2 and at the right of Fig. 1. The A operator then insorts the calling plug P into the jack J and thereby extends the calling line to the l% otlice. The supervisory relay 13 is thereupon actuated in a circuit closed from ground, left hand winding of relay 12, tip contacts of plug P and jack J, through the upper left hand winding of the repeating coil, through the high and low resistance windings of the relay 13 lower left hand winding of the repeating coil and the ring conductor of the trunk circuit, ring contacts of the plug P and jack J, through the right hand winding of relay 12 to grounded battery. Also, when the calling end of the cord circuit is connected with the trunk circuit, the sleeve rela'y 15 is actuated in a circuit closed through the sleeve contacts of the plug P and jack J. The relay 15 when actuated closes a break point in the circuit of the calling supervisory lamp 14:.

The relay 13 is actuated in the above de scribed circuit and at its lower armature and front contact closes an operating circuit for the slow releasing relay 16, which relay at its inner right hand armature and front con tact closes a circuit for lighting the incoming signal la'mp 17. The circuit from this lamp extends from ground, inner armature and front contact of relay l6. conductor 184 upper-most back contact and armature o f relay 19, conductor 20, lamp 1'? to grounded battery, not shown. The lighting of the lamp 17 indicates that the calling line has been extended to the assigned trunk circuit' The B operator has already received the designation of the wanted telephone line which it is assumed is shown at the right of Fig. 2 and then inserts the plug generally designated 21 into the multiple jack generally designated 22.

Since it is assumed that the wanted line is a party line, although only one of the sul-- stations is diagran'unatically shown, the operator depresses the proper frequency key for signalling the station D. lit is assumed that the ringing button 23 is the proper one for selecting the desired signalling current for selecting that wanted station. As soon as the plug 21 is inserted into the multiple jack 22, the sleeve relay 24: is operated in a circuit closed from grounded battery, sleeve contacts of the plug 21 and jack 22, and through the resistance which may be the cut-oil relay of the called line to ground.

lVith relay 24 operated, an actuating circuit for the slow releasing relay 25 is closed from grounded battery, winding of this relay, bacl: contact and continuity spring of relay 19, inner front contact and armature of relay it to ground. The relay 25 con nects the circuits of the five common ringing keys or buttons 23, 26, 2?, and 29 to the trunk circuit taken for use. hen the operator depresses the ringing button 23, the slow releasing relay 8O attracts its armaturcs and at its right hand armature and front contact closed a circuit from ground over the common conductor 31, innermost front contact and right hand armature of relay 25, winding of relay to grounded battery. The relay 32 is operated in this circuit and at its inner left hand front contact and armature con'rpletes a locking circuit for itself, over conductor inner front contact and armature of relay 2% to ground. Simultaneously with the actuation. of 32, the ringing relay 34; is operated in a circuit traceable from grounded battery, resistance, winding of this relay, conductor 35, front contacts and middle armature of relay 2, left hand armature and front contact of relay 30 to ground The ringing relay 3% also closes a locking circuit for itself through its lowermost front contact and armature, inner front contact and armature of sleeve relay 2%. to ground. r'it the same time that the relays 32 and 3 1- are operated, the relay 19 is actuated through its upper winding, middle armature and front contact of relay 25 and over the remainder of the circuit in multiple with the operating circuit of the relay 34:.

ll ith the ringing relay 34: operated and with the frequency selecting relay 32 actuated, ringing current from the 50 cycle source is connected to the wanted telephone line over a circuit now completed, through the outer left hand front contact and armature of the relay hack contact and armature of the rehu 86. back contact and armature of the relay 37, conductor 38. outer arn'ia'ture and trout contact of relay 16. conductor 39, winding of the trip relay 10. inner, lower front contact and armature of re lay 34, ringcontacts of the plug 21 and jack through the ringer of the sub-station D, over the upper side of the *alled line. tip contacts of the jack 22 and plug 21. inner upper armature and front contact ofrelay 34 to ground. Ringing current from the 50 cycle source is thus applied to the called telephone line, until the subscriber removes his receiver from its hook-switch, at which time the trip relay 4:0 is actuated and at its front contact and armature shOrt circuits the ringing relay 3a; which decuergizes, to close hreal; points in the trunk conductors. The supervisory relay 4-1 is thereupon actuated over the two sides of the truult. circuit and the two sides of the wanted telephone line in series.

Talking battery is. supplied to the calling party through the windings of the-supervisory relay 11, while talking battery is supplied to the called subscrihefls telephone through the windings of relay i1. Inac- 3ordance with one ofthe features of'the present invention, it' is proposed to provide a novel arrangementforthe supervision of the connection extending between the A and B ofiices. The connection of the A cord'circuit through the plug P andjack J to the trunk leading to the B ofiice', serves to complete an energizing circuit for the relay 13 as previously described, from ground theleft hand winding of relay 12, tip contacts ofthe plug P and jack J, upper winding of the repeating coil, through both windings in series of the relay 13, winding of the repeating coil, ring contacts of the jack J and the plug P, right hand winding of relay 12 to grounded battery.

The operation ofthe relay 1?) as previously pointed out effects the energization of the slow releasing relay 16. When, however, the called-party responds to the ringing signal and'removes his receiver from its switchhook, the supervisory relay at the B office attracts its armatures. This is effective to short circuit the high resistance winding of the relay 13 by a circuit traceable through the lower front contact andarmature of relay 4C1, the left hand from; contactand armature of relay 16 to the" upper winding of relay 18. At this time, l10"6V61,'tl16 relay 13 ismaintained energized through'its low resistance winding-in a circuit similar to that previously described, except that it now e-X- tends from the ring contacts of jack J, lower winding of'the repeating coil, low resistance winding of relay 13, left hand'front contact and armature of relay 16, lower armature and front contactof relay ll, upper winding'of the repeating coil to the tip of the jack J.

hen the called subscriber terminates the connection by replacing'his receiver on its switch hook, the supervisory relay 41 retracts its arn'iature and thereby removes the short circuit from the high resistance winding of the relay 13. This last named relay then includes both its high resistance and its low resistance windings in series with the supervisory relay 12 located at the A otlice. The relay 12 is so designed that it does not hold'its armature attracted when its energizingcircuit includes both windings of relay 13.

When relay 12 deenergizes, the supervisory lamp 14: lights in. a circuit now completed through the back contact and armature of relay 12 and the front contact and armature of relay 15. The A operator then removes the plug P from the jack J to disestablish the connection. If, however, the calling party at sub-stationG- has terminated the connection, the supervisorylamp 10 informs the A operator that the calling party has disconnected and the A operator then removes the plug P and the calling plug P of the A cord circuit from the jacks to which they were connected. As soon as plug This may arise when an A operator through mistake removes the plug P from the jack J, but immediately discovers her error and reestablishes the connection. In the former arrangements the high resistance of the relay corresponding to 13 was short circuited as long as the supervisory relaycore responding to 4-1 was operated, with the. result that under the condition just named, it was necessary to design the relay 13,-.s0 that it would attract its armature when energized only through its low resistance winding. Such a condition required very careful de sign of the relay 13 and even when the relay was installed in a commercial exchange, itrequired a great deal of attentionto maintain it in operation.

In accordance with the present invention, it is proposed to incorporate in the'system the slow releasing relay 16, which is controlled at a front contact and armature of the relay 13. Vi hen, therefore, the plugP is removed temporarily from the ack J, the relay 16 deenergizes so that even if the supervisory relay 41 is maintained-operated, the shortcircuit of the high resistance winding of. relay 13 is opened at the left hand armature and front contact of relay 16. This insures that the relaylS is operated through both windings in series, thereby securing a safer margin of operation.

In cord circuits en'iploying set of common ringing keys for a plurality of cord circuits, means must be provided to prevent the ringing of the called subscriber in the ear when ever the cord circuit temporarily disconnected from the called line and then the connection reestablished thereto- To take care of his con li ion, means z re provided to pre ringing current from reaching the ye i called suliiscribers sub-station on the reestablishing of a connection on such telephone line.

VJhen the plug 21 is removed from the multiple jack 22. of the called line, sleeve relay 24 deenergizes, but when the connection lit) is reestablished by the rccngagcment of this plug and jack, the sleeve relay 2d is again operated and closes acircuit from ground, its inner arn'iature and front contact, lower continuity spring and back contact of relay 1S), winding of the slow releasing relay to grounded battery. The relay 25 attracts its armatures and thereby completes another circuit from ground, armature and front contact of relay 24, outermost armature and frontcontact of relay 2;"), inner back contact and armatuie of relay 3%, through the tip contacts of the plug 21 and jack 22 through the subscribers line and sub-station at D, ring contacts of the r 22 and the plug 21, lower inner armature and back contact of relay 34, lower right hand winding of the repeating coil, lower winding of relay 4-1 to grounded battery.

With the relay ell. operated, the disabling relay 19 is actuated from grounded battery, its lower winding, upper front contact and armature of relay 41 to ground. Relay 1.) at its upper, inner armature closes a break point in the talking circuit and its lower armature and continuity spring closes a locking circuit for itself, which circuit is completed at the frontcontact and arn'iature of the relay 2d. As soon as the disabling re lay 19 is operated, it opens the circuit of the slow releasing relay 25, at its back contact and continuity spring. It will be noted that the relay 25 controls a break in the energizing circuit of the ringing relay 34: and also controls break points in the circuits by which the ringing keys selectively operate the selective ringing relays 32, 36 and. 37. Itwill thus be seen that whenever a trunk circuit is connected to a called line, at a time when the called subscribers receiver is oti' the switchhook, the relays 19, 25 and ll operate in the manner justdescribed to prevent ringing current from reaching the called subscribers line.

It will be understood that the present disclosure merely illustrates one modification of applicants invention and should in no way be construed as limiting the scope of the appended claims.

lVhat is claimed is:

1. In a telephone system, a primary oliicc, a second office, a plurality of telephone li cs at said otiices, a supervisory signal at said primary ofiice, a supervisory relay tor controlling the same, a second relay at said second ofiice, a supervisory circuit including said relays in series, said second relay having a high resistance winding and a low resistance winding, said supervisory relay being of such value as not to operate in series with said high resistance winding, a third relay actuated by the response of the called party, a slow releasing relay, a circuit controlled by said third relay and by said slow releasing relay for completing a circuit for said second relay through its low resistance Winding independently of said hight resistance winding, said slow releasing relay being responsive to all releases olf said second relay for including said high resistance winding in said supervisory circuit.

2. In a telephone system, a primary oliice, a second otlice, a plurality of telephone lines at said oiiices, a supervisory signal at said primary ofiice, a supervisory relay for controlling the same, a second relay at said second ofiice, a circuit extending between said oflices serially including said supervisory rc lay and said second relay, said second relay having a high resistance winding and a low resistance winding, said supervisory relay being of such value as not to operate in series with said high resistance winding, a third relay actuated by the response of the called party, a slow releasing relay controlled by the operation of said second relay, means including said slow releasing relay and said third relay for placing a shunt circuit about said high resistance winding, and means including said slow releasing relay responsive to all deenergizations of said second relay for opening said shunt circuit.

3. In 'a telephone system, telephone lines, cord circuits and link circuits for interconmeeting said telephone lines, each link circuit having sections inductively connected together, a first supervisory relay bridged across one section, and a second superwisory relay bridged across another section of each link circuit, a third supervisory relay bridged across each cord circuit, said third relay and said first supervisory relay being included in a circuit extending through a cord circuit and a link circuit when a connection is established, said first supervisory relay having a high and a low resistance winding whereby said third relay is not operated in series therewith, means including said second supervisory relay for removing said high resistance winding from said circuit whereby said first relay is operated, and means for including said high resistance winding in said circuit whenever said first relay deenergizes even when said second relay is operated.

4i. In a telephone system, a plurality of telephone lines, a plurality of link circuits, a supervisory relay for each link circuit, a ringing key common to said circuits, a source of ringing current, a second relay in each link circuit for connecting said key to its link circuit, a circuit for initially energizing said second relay, a circuit including contacts of said second relay and a winding of the SUPGIVlSOI'y relay, a third relay, a circuit for said third relay, completed at said supervisory relay, and means controlled by said third relayfor disabling said second relay.

5. In a telephone system, telephone lines,

a plurality of link circuits for interconnecting said telephone lines, a source of ringing current, a ringing key common to said link circuits, a ringing circuit controlled by said ringing key extending over a link circuit to a Wanted telephone line, a cut-in relay in each link circuit operated responsive to the connection of said link circuit to a Wanted telephone line for placing said ringing circuit under the control of said ring-- ing key, a supervisory relay operatedvby the response of the subscriber on the Wanted telephone line, a sleeve relay energized While said link circuit is connected to the Wanted line, a circuit for said cut-in relay completed at said sleeve relay, an operating circuit for said supervisory relay including its Winding and contacts of said cut-in relay, means including a disabling relay for disabling said cut-in relay, and a circuit for said disabling relay completed at said supervisory relay.

6. In a telephone system, a plurality of telephone lines, a plurality of link circuits, a supervisory relay for each link circuit initially energized over its link circuit, signaling means common to said circuits, a source of ringing current and a second relay in each link circuit for connecting said signaling means to said link circuit, a circuit for initially energizing said supervisory relay, a second circuit for said second relay including its own winding and contacts of said second relay, a third relay, a circuit for said third relay, normally completed in part by said signaling means, another circuit for said third relay completed at said supervisory relay, and means controlled by said third relay for disabling said second relay.

7. In a telephone system, telephone lines, a plurality of link circuits for interconnecting said telephone lines, a source of ringing current, signalling means, including a ringing key common to said link circuits, signalling devices controlled by said signalling means for supplying signalling current over a link circuit to a Wanted telephone line, a sleeve relay energized when said link circuit is connected to the Wanted telephone line, a second relay in each link circuit normally operated by the energization of said sleeve relay for placing said signalling devices under the control of said signalling means, a supervisory relay operated by the response of the subscriber on the Wanted telephone line, a circuit for said supervisory relay, ineluding its own Winding and contacts of said second relay, means including a relay for opening said last mentioned circuit, and a circuit for said last mentioned relay completeol at said supervisory relay.

In Witness whereof, I hereunto subscribe my name this 27 day of September, A. I). 1923.

JOHN H. LEVIS, JR. 

